Manufacture of 1-amino-2-alkoxynaphthalenes



Patented Jan. 17, 1933 UNITED STATES momma) T=OBLER,- E RIEHEN, NEAR. BASEL, Ann WALTER KERN, or srssnon, SWITZERLAND, ASSIGNORS 'rO THEEIRM or" socrError CHEMICAL INDUSTRY IN.

i AsL oF BASEL, SWITZERLAND PATENT, OFFICE MANnE oTUEE or 1-AMINO- 2-ALKOXYNAPHTHALENES No Drawing. Application, filed. January 25,1932, Serial N o.[ 588,812, and in Switzerland February 9, 1931.

raisedtemperature with an agent that yields amrnonia, advantageously in presence of a substance whichf'acilitates the exchange "of the halogen.

f I Suitable 1-halogen 2-alkoxynaphthalenes are, for instance, 1-chloro-2-methoxynaphthalene, 1 bromo 4 2 methoxynaphthalene; also the corresponding Oethylated or O-propylated compounds. a

Substances Which facilitate the exchange of halogen are, in particular, finely divided copper andits compounds, such as for 1nstance copper hydroxide, copper sulfate, andzinc chloride.

. In many cases it is of advantage to add to the mixture undergoing reaction an organic solvent, such as methyl-or :ethyLalcohol, or pyridine, which is capable of dissolving the 1-halogen-2-alkoxynaphthalene The temperature at which the reaction is to occur may vary within wide limits. Generally speaking, I when 1-'chloro-2-alkoxynaphthalene isused, the temperature selected must be higher than when the corresponding bromo-derivative is used; the latter reacts when heated with ammonia in'an autoclave already at temperatures from about 110120. 'As agents yielding ammonia there come 1 into consideration for [instance ordinary aqueous ammonia, urea, ammonium chloride, ammonium carbonate, ammomum b1- carbonate, zinc chloride-ammonia; very good yields are. obtained, for example, wlth an aqueous solutlon of ammonia of as high a strength as possible in presence of finely'dividedcopper anda little alcohol. ,WVhen copper is used as the agent for facilitating the exchange of the halogen there are formed,

owing to the reducing action ofjthe copper' and according to the proportion of added co pp er,to the duration'of the reaction and to the temperature of the reaction, besides the 1-amino-2-alkoxynaphthalene, a smaller or larger quantity of, 2 -alkoxynaphthalene, which. may be isolated, halogenated andfurther calrsed to react with'amm-onia or an agent that yields ammonia.

The following examples illustrate the invention, the parts being'by weight I E wample 237 parts of 1-bromo-2-methoxynaphthalene, 3000 parts of ammonia (of 32 per cent.

strength) and 10 parts of natural copper 0 (cf. Berichte der deutschen chemischen Gesellschaft volume 29, footnote at pages 187 8- a 7 '79) are charged into, an autoclave; for in creasing the concentration, ammonia gas is introduced. The internal temperature of the autoclave is now raisedto 110115 C. and kept at this point for 40 hours. After cooling and blowing off the excess of ammonia, the contents of the autoclave are discharged and then mixed with ether and the ethereal layer is separated in a separating funnel. The dried ethereal solutionis then. 1

saturated with hydrochloric acid gas so that the 1-aminoe2-methoxynaphthalene' is pre- .cipitated substantially quantitatively in the form of hydrochloride. The latter is filtered and dried. In order to obtain the free 1 amino-2-methoxynaphthalene the hydrochloride is dissolved in 6000 parts of water, the

In thismanner a good yield of 1-amino-2- methoxynaphthalene is obtained in the form of colorless needles which'melt at 54 Example 2 clave. For increasing the concentration, am-.

monia gasis introduced fora period of some m1nutes;the 1nternal temperature of the autoclave is thenraised to 110115 C'., and

maintained at that temperature for 50 hours. 7

'After cooling and blowing off the excess of 'ammonia,-the contents of the autoclave are discharged and mixed with ether and the ethereal layer is then separated in a separating funnelJ Hydrochloric acid gas is led into the'dried ethereal solution until the lat- 'ter is saturated'with the gas, whereby 1- amino-2-ethoxynaphthalene is precipitated in the form of the hydrochloride. The lat teris filtered and dried. In order to obtain Instead of copper, other suitable substances may be used, such as zinc chloride or' sodium .sulphite;

Example 237 parts of 1-bromo-2-methoxynaphthalene, 3000 parts of ammonia of 32 per cent.

strength, 10 parts of natural copper C andparts of alcohol are charged into-an auto:

clave, and for increasing the concentration ammonia gas is introduced for a period'o-f some minutes. The internal temperature is then raised to 110-115 C. and kept at this temperature 'for hours. The cooled contents of the autoclave are now filtered, whereby the 1 amino 2- methoxynaphthalene,

which is insoluble in ammonia and a little copper are separated from the solution. This 'undissolved matter is thoroughly extracted with sulfuric acid of 5 per cent. strength at 'a temperature of 60-7 0 C. and the filtrateis ;ll.' W made a mline wlthammonia In th1s man amin0 2 alkoxynaphthalenesa rconslstgmglm moo causing 1-halogen-2-alkoxynaphthalenes to nor the 1-amino-2-methoxyn aphthalene is obtained ingood yield in the form of a precipitate which can be'separated by simple filtration. p

v Example .4

192.5 parts of 1-chloro-2-methoirynaphthalene, 2000 parts of ammoniaof' 32 per cent.- ,strength, 100 parts of 'alcoholand 15 parts of natural copper C arecharged into an autoclave; for increaslng the concentration ammonia gas is introduced. The autoclave is heated until its internal temperature is 135-140 C., at which it is maintained during 40 hours. After working up as described thalene is obtained in the form of pale yellow needles which melt at C.

Example 5 g parts. of 1-bromo-2 methoxynaphthalenearemelted during 9 hours" at 180-185 C.

together with 300 parts of urea; The cooled mass is-dissolved in dilute hydrochloric acid at-70 C. and the unchanged 1-brom'o-2- methoitynaphthalene is separated by filtration.

The hydrochloric acid solution of l-aminomethoxynaphthalene-hydrochloride is preing ammonia.

cipitated in the form of white'needles which 7 are separated by filtration. 1

7 Example 6 its internal temperatureis 1104155 6., which temperature is maintained during 40 hours.

Aftercooling and blowing off excess of am; I monia the contents of the autoclave areidis charged, filtered and the solidv matter washedwith water. This solid matter is then mixed with-105 parts of sulfur'icacid of97 per cent.

strength and 1250parts of water, and the whole is subjectedto steam distillation 2 5 methoxynaphthalene of melting point 7 29C. distils owing to the elimination of bromine r. from the l-bromo-2-methoxynaphthalene. The residual sulfuric acid solution is now filtered from a little impurity and mixed 02 with 200 parts of concentrated hydrochloric acid, and the solution is then saturated with common salt. The 1-amino-2-methoxynaph thalene-hydrochloride is thus separated in theform ofa crystalline precipitate, which @43 maybe filtered, washed with concentrated salt solution and dried.

What we claim is: 1 v 1 1. A process for the manufacture .of 1- react at raised temperature with agents yield- 2. A process for, the manufacture of 1.-

.amino-2-alkoxynaphthalenes, consisting .in E causing l-halogen-Q-alkQXynaphthalenes toreact. at raisedtemperature v with ammonia.

3. A process for the manufacture ofit amino-2-alkoxynaphthalenes, consisting in causing l-halogien-Q-alkoxynaphthalenes to react at raised temperature witlr ammonia,

in presenc'eof compounds of copper, and of organic solventswhich have a dissolvingac- .t' th -1h l -2- 1k hth l e. in Examplel the l-amino-2-methoxynaphl Oge'n a oxynap am 5 organic solvents whichhave a dissolving ac tion ofthe 1-halogen-2-alkoxynaphthalenes.

5. A process for the manufacture of 1-.

amino -alkoxynaphthalenes, 7 consisting in;

causing 1-halogen-2-alkoxynaphthalenes to react at raised temperaturewith 5 ammonia,

in presence of finely alcohols. p

6.; A process for the manufacture ofldivided copper, and of amino-2-methoxynaphthalene, consisting in causing 1-halogen-2-methoxynaphthalene to react at raised temperature with ammonia in presence of finely divided copper and of I alcohols.

7. A process for-the manufacture of 1- amino-2-meth0xynaphtha1ene, consisting in causing l-bromo-2-meth0xynaphthalene to react at raised temperature with ammonia in presence of finely divided copper and of alcohols.

8. A process for the manufacture of 1- amino-2-methoxynaphtha1ene, consisting in causing 1-br0m0-2-methoxynaphthalene to react at raised temperature with ammonia in presence Of finely divided copper and of ethylalcohol.

In witness whereof we have hereunto signed our names this 14th day of January, 1932.

RICHARD VTOBLER.

WALTER KERN. 

